This scroll wouldn't fulfill the biblical commandments of writing a Torah scroll (Chinukh #613), reading from a Torah scroll on Sukkot following Shemitta (#612), or a king writing a Torah scroll (#503), nor would it get the same level of respect (#257) as a kosher Torah scroll such as when stacking scrolls (YD 282:19) or according to some standing when it is in movement (ibid. :2).

Question: Why is a Torah written by a woman not considered a kosher Torah? Or more precisely, how was the conclusion drawn that a Torah written by a woman is not kosher?

R. Hamnuna the son of Raba of Pashrunia learnt that a scroll of the Law, phylacteries and mezuzoth written by... a heathen, a slave, a woman, a minor... are disqualified, since it says. And thou shalt bid them … and thou shalt write them, which indicates that those who are subject to 'bind' may 'write', but those who do not 'bind' may not 'write'. (Soncino translation)

In other words, the Talmud derives from the fact that the primary example of ritual writing is juxtaposed (in the verses in Shema) to the commandment of Tefillin, which only Jewish adult free men are obligated in, that ritual writing for a Torah scroll, Tefillin and Mezuzot (the Mitzva objects which can be created by a specific writing process) must be performed by Jewish adult free men.

(As noted in the answer there, she can write books of Tanakh, just writing the five books of the Torah wouldn't create a "Torah scroll" but rather something more like a Chumash, just like her writing the text of a Mezuzah wouldn't create a Mezuzah but rather just an object that could be used to read Shema from or something. The exclusion above is from the ability to create those three Mitzva objects, not from writing itself.)

If I am correct, the quoted text: "since it says. And thou shalt bind them..." is taken from Deuteronomy 6:8–9. Could you add some information how that verse is related to the "kosherness" of a torah written by a woman for instance, or why it is used as a analogy in your quote? Maybe some further information on the meaning of the word "bind". +1 However!
– KiliseNov 14 '17 at 18:02

@Kilise Deut 6:8-9 and also Deut 11:18-20. I explained in the post that the juxtaposition of "writing" to "tying" is used to indicate who is eligible to write, namely, those who are obligated to tie. To try again in other words, those who are obligated to tie [Tefillin] are eligible to create the three Mitzva objects which are created via writing: Torah scrolls, Tefillin and Mezuzot. (I don't know what your background is so I'm not sure how much I need to be explaining. Do you know what Tefillin and Mezuzot are?)
– Double AA♦Nov 14 '17 at 18:06

Actually, I think that (1) the resulting scroll would be somewhat holier than a chumash, but only because hand-written is holier. A chumash manuscript is holier than a printed chumash; in fact when printing became commonplace, there was even a question of whether printed texts that contained G-d's name required burial. Which we answered yes; although it might be the "yes" is minhag, not halakhah. And (2) it would still require burial, as it could be confused with a kosher Torah and might lead a minyan to accidentally miss the mitzvah of Torah reading.
– Micha BergerNov 15 '17 at 16:31

@MichaBerger A chumash is a handwritten scroll of a book of Torah. Those books with printed torah texts are just books, and they are not nearly as holy as real chumashim. This is already noted by the Rama (YD 283:1, cf. Arukh haShulchan ad loc). I could have discussed this in detail but it wasn't very relevant to the main thrust of the answer.
– Double AA♦Nov 15 '17 at 16:32